Information processing apparatus and method

ABSTRACT

In an information processing apparatus, a program processing unit executes a program described as an object-oriented language executed by a platform-independent machine language. A monitor unit monitors a change of a network address of the information processing apparatus. A reference provision unit provides a new network address of the information processing apparatus for another information processing apparatus when said monitor unit detects the change of the network address of the information processing apparatus.

FIELD OF THE INVENTION

[0001] The present invention relates to information processing apparatusand method for executing distributed information processing in a Java(Registered trademark of Sun Microsystems INC.) executive environment.

BACKGROUND OF THE INVENTION

[0002] Recently, by development of program executive environment Java(Ken Arnold, James Gosling, “The Java Programming Language, SecondEdition,”) independent from a platform, a system to cooperate variouskinds of information equipments with Java is greatly taken intoconsideration. In case of implementing a distributed application byJava, in general, a communication mechanism, “Remote Method Invocation(RMI)”, is utilized as communication means (Troy Bryan Downing, “RMI:Developing Distributed Java Applications with Remote Method Invocationand Serialization,” IDG Books World Wide, Inc. 1998). RMI is an extendedversion of method invocation mechanism between objects in Java. RMI is asimple and powerful communication mechanism that conceals a complicatedcommunication processing. However, Java and RMI cannot adjust to achange in the IP address (Hereinafter, called “network address”) of theexecutive computer (host). The following two problems then arise.

[0003] (1) When a client connects to a server, in RMI, the connection isexecuted using information “remote reference”. The remote referenceincludes the network address (IP address) and a port number of thecomputer executing a server program. For example, when the computer isactivated (power is turned on) and the service is disclosed, the serverprogram creates the remote reference. In this case, the network addressat the creating time is written in the remote reference. If the networkaddress is changed, a mechanism to update the remote reference is notprepared. Accordingly, after the network address changes because thecomputer moved, the remote reference distributed by the server program(to register to a directory service program) includes the networkaddress before the computer moved. After a client program receives thisremote reference, the client program tries to connect to the serverusing the old network address. The client program cannot connect to theserver having the new network address.

[0004] (2) In the RMI, a Java object is sent and received between theserver and the client. In the Java program receiving side, a class filecorresponding to received Java object is necessary. If the Java programalready has the class file, the Java program executes processing ofreceived Java object using the class file. However, if the Java programdoes not have the class file, the Java program refers to information ofsupply source of the class file annotated to the Java object, anddownloads the class file from the supply source. After that, the Javaprogram executes processing of the Java object. The information ofsupply source of class file annotated to the Java object is called“codebase”. The codebase is indicated by Uniform Resource Locator (URL)format. In the same way as the remote reference, the codebase is static,and the codebase does not have an update mechanism in cooperation with achange of the network address. Accordingly, if a computer whose networkaddress dynamically changes such as network moving is the supply sourceof a class file (in case that HTTP server is executed on a servermachine), the codebase is not updated and a program at the receivingside cannot normally operate.

BRIEF SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide aninformation processing apparatus and method for, even if the networkaddress of a terminal including Java program dynamically changes,communicating to another terminal including Java program by updating theremote reference and the codebase.

[0006] According to an aspect of the present invention, there isprovided an information processing apparatus, comprising: a programprocessing unit configured to execute a program described as anobject-oriented language executed by a platform-independent machinelanguage; a monitor unit configured to monitor a change of a networkaddress of the information processing apparatus; and a referenceprovision unit configured to provide a new network address of theinformation processing apparatus for another information processingapparatus when said monitor unit detects the change of the networkaddress of the information processing apparatus.

[0007] Further in accordance with another aspect of the presentinvention, there is also provided an method in an information processingapparatus, comprising: executing a program described as anobject-oriented language executed by a platform-independent machinelanguage; monitoring a change of a network address of the informationprocessing apparatus; and providing a new network address of theinformation processing apparatus for another information processingapparatus when the change of the network address of the informationprocessing apparatus is detected.

[0008] Further in accordance with another aspect of the presentinvention, there is also provided a computer program product,comprising: a computer readable program code embodied in said productfor causing an information processing apparatus, said computer readableprogram code having: a first program code to execute a program describedas an object-oriented language executed by a platform-independentmachine language; a second program code to monitor a change of a networkaddress of the information processing apparatus; and a third programcode to provide a new network address of the information processingapparatus for another information processing apparatus when the changeof the network address of the information processing apparatus isdetected.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a component example of a distributed informationprocessing system.

[0010]FIG. 2 is a block diagram of a virtual machine executing aconventional server program.

[0011]FIG. 3 is a flow chart of processing of the server programaccording to various embodiments of the present invention.

[0012]FIG. 4 is a flow chart of processing of the client program.

[0013]FIG. 5 is a block diagram of the virtual machine executing theserver program according to various embodiments of the presentinvention.

[0014]FIG. 6 is a block diagram of another virtual machine executing theserver program according to various embodiments of the presentinvention.

[0015]FIG. 7 is a schematic diagram showing a method of detectingchanges in a network address.

[0016]FIG. 8 is a schematic diagram showing another method of detectingchanges in a network address.

[0017]FIG. 9 is a flow chart of a remote reference update processingaccording to various embodiments of the present invention.

[0018]FIG. 10 is a schematic diagram showing a communication conceptusing RMI of Java.

[0019]FIG. 11 is another component example of the distributedinformation processing system.

[0020]FIG. 12 is a block diagram of another virtual machine executing aserver program according to various embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, various embodiments of the present invention will beexplained by referring to the drawings. FIG. 1 is a component example ofa distributed information processing system. A plurality of computers(In FIG. 1, three computers) 101, 102 and 103 are connected through anetwork such as the Internet. Each computer includes at least oneexecutive environment (Java virtual machine) executing a programdescribed by Java. Java is an object-oriented language executed bymachine language independent from a platform. The distributedinformation processing is realized by communication between Javaprograms using RMI.

[0022] The distributed information processing using RMI of Java requiresa server program providing a service, a client program utilizing theservice, and a directory service program mediating between the serverand the client. In FIG. 1, the server program, the client program andthe directory service program are respectively programs executed by Javavirtual machine S, C, D, on different computers 102, 103, 101. In thiscase, different Java virtual machines on the same computer may be used.

[0023] The directory service program allows a client program to detectthe server program. The directory service program detects the serverprogram using a key such as a service name or a service attributerequested from the client program. For example, a program “rmiregistry”,included in development environment of Java, and a program “LookupServer” of Jini (K. Arnold, B. O'Sullivan, R. W. Scheifler, J. Waldo,and A. Wollrath, “The Jini Specification,” Addison-Wesley, 1999),advocated by Sun Microsystems INC., are example directory serviceprograms.

[0024] The server program receives a service request from the clientprogram on other Java virtual machine as a format of remote methodcalling, and sends back the service result as a returned value of themethod. In case of beginning the service provision, the server programwrites a service name and a service attribute provided by the serverprogram, and information necessary for connecting to the server program,in an object file explained afterwards. The information is called “aremote reference”. The information includes a network address (networklayer address, i.e., IP address), a port number, and an objectidentifier. The server program registers the object file in thedirectory service program.

[0025] The client program sends a request using the remote methodcalling to the server program, and receives a response (service result)from the server program. In case of accessing the service, the clientprogram must know a location of the server program operating on thenetwork. Accordingly, the client program first connects to the directoryservice program, and retrieves desired server program using a key suchas a service name or a service attribute. In case of succeeding in theretrieval, the client program can acquire a remote reference registeredin the directory service program. The client program connects to theserver program using the remote reference, and receives the serviceprovision from the server program.

[0026] The Java virtual machine prepares a remote reference control unitin order to utilize RMI. The remote reference control unit controls tocreate a remote reference for an object in the same Java virtual machineand to receive a remote reference for another object from another Javavirtual machine. In this case, assume that a server program to providesome service is created in Java virtual machine S and a client programin another Java virtual machine C accesses the server program. First,the case of no moving (no change in the network address) is explained.FIG. 2 is a block diagram of the virtual machine S on which a serverprogram operates. FIG. 3 is a flow chart of processing of the serverprogram according to the present embodiment. In FIG. 2, the virtualmachine S includes a server object 2, a registration control unit 3, aremote reference control unit 4, and a network address acquisition unit5. In general, the server program of Java includes a plurality of Javaobjects. In the plurality of Java objects, an object receiving a remotemethod calling by RMI is included. This object inherits the class“java.rmi.server.RemoteServer”. Hereinafter, this object is calledserver object 2.

[0027] The remote reference control unit 4 includes a remote referenceupdate unit 4 a and a remote reference memory 4 b. The remote referenceupdate unit 4 a creates and updates a remote reference for the serverobject 2, and stores the remote reference in the remote reference memory4 b. Furthermore, the remote reference control unit 4 receives a remotereference to refer an object in another Java virtual machine. Theregistration control unit 3 registers the remote reference for theserver object 2 stored in the remote reference memory 4 b to a directoryservice program in the Java virtual machine D. The network addressacquisition unit 5 acquires a network address of a computer 102 from anoperating system (For example, Windows (registered trademark ofMicrosoft Inc.), Linux (registered trademark of Linus Torvalds), and soon. Hereinafter, called “OS”.) of the computer 102 when the serverobject 2 is generated (operated, i.e., class is instanced). The“getLocalHost ()” method provided by “java.net.InetAddress” class is oneexample. In JDK (Java Development Kit) 1.1 and JDK 1.2 offered by SunMicrosystems INC., in case of acquiring a network address, the networkaddress is continually preserved until the Java virtual machine iscompleted. The remote reference update unit 4 a writes a network addressacquired by the network address acquisition unit 5 in a remotereference.

[0028] When the computer 102 is activated and the server object 2 isgenerated by the Java virtual machine (class is instanced) (S1 in FIG.3), the remote reference control unit 4 extracts a network address fromthe network address acquisition unit 5, creates a remote reference forthe server object 2, and stores it in the remote reference memory 4 b(S2). Next, the registration control unit 3 registers the remotereference for the server object 2 to the directory service program D(S3).

[0029]FIG. 4 is a flow chart of processing of a client program. Theclient program includes a plurality of Java objects. Hereinafter, theyare called client objects. In order to retrieve a server programproviding a desired service, the client program connects to thedirectory service program, and retrieves the desired server program byusing a key such as a service name or a service attribute (S11 in FIG.4). When the client program acquires a remote reference for the desiredserver program from the directory service program (S12), the clientprogram connects to the desired server program using a network addressdescribed in the remote reference (S13), and receives the serviceprovision (S14). As mentioned-above, operation of the server program ofS1˜S3 in FIG. 3 is the same as in the prior art.

[0030] Next, as for the operation of the server program of the presentembodiment, the case of the computer's moving (a network addresschanges) is explained. Assume that the network address of the computer102 on which the server program is operating is changed. For example, auser carries a mobile computer such as a portable notebook personalcomputer. While moving or suspending the mobile computer, the userconnects the mobile computer to another IP network (Hereinafter, it iscalled network). Furthermore, in case that a non-movable computer suchas a desktop computer is connected by dial-up, when a telephone line isreconnected after disconnect once, another network address is oftenassigned to the non-movable computer. In this way, assume that thenetwork address of the computer 102 is changed during the serverprogram's operating. In this case, after the IP network of the computer102 is changed, the server object 2 is not generated again. In a remotereference for the server object 2 stored in the remote reference memory4 b, a network address at the time the server object 2 was generated iscontinuously preserved. Accordingly, update of the remote reference isnecessary based the new network address.

[0031] When the network address acquisition unit 5 acquires a networkaddress once, the network address acquisition unit 5 preserves a valueof the network address, and informs the value to the remote referencecontrol unit 4 after the network address is changed. Accordingly, thenetwork address acquisition unit 5 must delete the value of previousnetwork address and acquire a new network address in case of calling. Inshort, when a network address of the computer 102 on which a serverprogram is operating is changed, a mechanism to detect the change in thenetwork address of the computer 102 is necessary to quickly update theremote reference. This mechanism may be prepared by OS managing theaddress network. As shown in FIG. 5, a program monitoring the addressnetwork (network address monitor 6) may always exist outside of the Javavirtual machine S. In these cases, a change in the network address fromoutside of the Java virtual machine S is sent to the remote referencecontrol unit 4 (the remote reference update unit 4 a) may be prepared.Thus, a normal communication between processes such as socket may beutilized. Furthermore, as shown in FIG. 6, the network address monitor 7may exist in the Java virtual machine S.

[0032] A function of the network address monitor 6 in FIG. 5 isexplained by referring to FIG. 7. The network address is acquiredthrough a Protocol such as DHCP (Dynamic Host Configuration Protocol) 12or PPP (Point-to-Point Protocol) 13 if necessary, supplied to OS 11 inthe computer 102, and preserved in OS 11. The network address monitor 6periodically reads out a network address stored in OS 11, and comparesthe network address with a previous network address read out at aprevious time. If a present network address is different from theprevious network address, the network address monitor 6 informs theremote reference control unit 4 (the remote reference update unit 4 a)of the difference using the normal communication such as a socket. Onreceiving the communication, the remote reference update unit 4 aacquires a new network address by activating the network addressacquisition unit 5.

[0033] Furthermore, a function of the network address monitor 7 in FIG.6 is explained by referring to FIG. 8. In the same way as theabove-mentioned explanation, a network address is acquired through aProtocol such as DHCP 12 or PPP 13 loaded on the computer 102, andpreserved in OS 11 of the computer 102. The network address monitor 7periodically calls the network address acquisition unit 5, compares anetwork address acquired by the network address acquisition unit 5 witha previous network address, and detects whether the network address ischanged. In case of detecting a change in the network address, thenetwork address monitor 7 calls a method of the remote reference updateunit 4 a, and informs the new network address.

[0034] This explanation now returns to FIG. 3. After detecting a changein the network address and acquiring a new network address, the remotereference update unit 4 a updates a network address in the remotereference stored in the remote reference memory 4 b (S5). The remotereference memory 4 b stores a plurality of remote references. Theplurality of remote references are divided roughly into references forobjects in the same Java virtual machine and references for objects inanother Java virtual machine. The remote references to be updated bychange of network address are only the references for object in the sameJava virtual machine. In this case, a remote reference update processingof the remote reference update unit 4 a at S5 in FIG. 3 is explained byreferring to a flow chart in FIG. 9. The remote reference update unit 4a selects one remote reference of unprocessing for objects in the sameJava virtual machine from the remote references stored in the remotereference memory 4 b (S21, S22). If the selected remote referenceincludes a previous network address before the computer 102 moved (S23),the remote reference update unit 4 a updates the previous networkaddress with the new network address (S24).

[0035] As a method for detecting changes in the network address,periodical monitoring is not always necessary. The monitor may beexecuted at each first network access after the computer moves. Theremote reference must be updated each time a program of the Java virtualmachine S of the computer 102 communicates with another Java virtualmachine of another computer. For example, as shown in FIG. 5, when thecomputer 102 replies to a packet received by a program outside of theJava virtual machine S, the network address monitor 6 checks the networkaddress. If the network address is changed, the network address monitor6 calls a method of the remote reference update unit 4.

[0036] As mentioned-above, the case of updating the network address inthe remote reference by change of the network address was explained.However, actually, accompanying with the change of the network address,object to be updated is not limited to the remote reference only. First,a concept of communication using RMI of Java is explained by referringto FIG. 10. In RMI of Java, when a client program of computer 103 callsa remote method supplied by a server object 2 of the computer 102, astub class of the server object 2 is necessary. Furthermore, the serverprogram includes a skeleton class corresponding to the stub class. Ifthe stub class of the server object 2 is not included in the computer103 executing the client program, the client program downloads a filedescribing the stub class (stub file) from the server object 2 accordingto an address indicated by a codebase included in a stub object of adirectory service program 101. The stub object includes the remotereference and the code base. The stub file exists in the computer 102operating the server program. Alternatively, the stub file exists in adifferent computer. As mentioned-above, the former case is affected by achange in the network address accompanying with the computer's moving.When the stub file is provided to the client program of the computer103, HTTP (Hyper Text Transfer Protocol) is normally utilized.Accordingly, as shown in FIG. 11, in the computer 102 operating theserver program, an HTTP server 104 to send a data file by HTTPconcurrently operates. In FIG. 10, a stub file of the server object 2 tobe provided from the server program of the computer 102 to the clientprogram of communication party is stored in the HTTP server 104 (S101 inFIG. 10). Furthermore, the codebase represents a location address of thestub file of the server object 2. This codebase is added to the stubobject when the stub object is sent to the directory service program inorder to register (S102 in FIG. 10, S2 in FIG. 3). The client programreceives the stub object of desired server program from the directoryservice program (S103 in FIG. 10), accesses to provision source (HTTPserver) of the stub file by referring to the codebase in the stubobject, and downloads the stub file (S104 in FIG. 10). After that, theclient program executes the operation following from S13 in FIG. 4.

[0037] A store location of the stub file of the server object 2 isincluded in the computer 102. As mentioned-above, if the network addressof the computer 102 operating the server program is changed, the remotereference must be updated. In addition to this, the codebaserepresenting a location of the stub file must be updated because thenetwork address of HTTP server 104 providing the stub file is alsochanged.

[0038] In RMI, a class loader for RMI is defined. The class loader forRMI manages the stub class and the skeleton class of RMI, and classsupplied as parameter or return value of method of RMI. Concretely, theclass loader for RMI retrieves and loads a plurality of class files inorder, and stores location addresses from which each class is loaded. Incase of sending an object to another Java virtual machine, the classloader annotates a URL representing the location address to the objectin order for the receiving side to load the class corresponding to theobject. In case of annotating a codebase representing location addressof the stub class and the skeleton class, a value in the local codebasemanaged by the class loader is copied to the codebase (Details aredisclosed in the RMI specification). In this local codebase, an initialvalue is indicated by property at the time of activation.

[0039] As shown in FIG. 12, a virtual machine S operating a serverprogram includes the class loader 8 for RMI. In FIG. 12, the same signis assigned to a unit the same as in FIG. 2 and FIG. 5. Hereinafter,different units are explained. In case of a change in the networkaddress of the computer 102, a value in a local codebase 8 a managed bythe class loader 8 must be updated. Accordingly, if the change in thenetwork address is detected, a codebase update unit 8 b is called, andthe value representing the computer 102 in the local codebase 8 a isupdated using the new network address. For example, assume that thenetwork address of the computer 102 is “100. 101. 102. 103” and thecodebase is “http://100. 101. 102. 103/codebase/”. If the networkaddress of the computer 102 is changed to “200. 201. 202. 203”, thecodebase is updated as “http://200. 201. 202. 203/codebase/”. As shownin FIGS. 7 and 8, detection of changes in a network address is executedoutside of the Java virtual machine S (FIG. 7) or inside of the Javavirtual machine S (FIG. 8). In FIG. 12, the network address monitor 6exists outside of the Java virtual machine S.

[0040] As mentioned-above, when the network address monitor 6 detects achange in the network address, the network address monitor 6 informs thepurport to the remote reference control unit 4 (the remote referenceupdate unit 4 a) and the class loader 8 (the code base update unit 8 b)of the change using a normal communication between processes such as asocket. On receiving this indication, the remote reference update unit 4a and the codebase update unit 8 b acquire the new network address byactivating the network address acquisition unit 5. The codebase updateunit 8 b updates the local codebase 8 a using the new network address.At S5 in FIG. 3, the remote reference update unit 4 a updates the remotereference using the new network address and updates the local codebase 8a by the codebase update unit 8 b. Then, the remote reference updated bythe remote reference update unit 4 a is registered to a directoryservice program existing on an IP network of moving destination of thecomputer 102 (S3 in FIG. 3). This directory service program is notlimited to a program operated in the computer 101. In this way, theremote reference update unit 4 a updates the network address in theremote reference according to the change in the IP address incooperation with moving of the computer 102. At a moving destination ofthe computer 102, updated remote reference and updated codebase areassigned to the stub object, and the stub object is registered to thedirectory service program. As a result, the server program in thecomputer 102 can communicate with the new client.

[0041] As mentioned-above, in the computer 102 including at least oneJava virtual machine S executing the server program, when the networkaddress monitor 6 or 7 detects a change in the IP address of thecomputer 102, the network address in the remote reference and thecodebase are updated. A stub object including updated remote referenceand updated codebase is registered again to the directory serviceprogram. Accordingly, even after change in the IP address of thecomputer 102, a client can access to the server program.

[0042] In the above-mentioned explanation, the stub file is used as anexample. However, the present invention is not limited to this example.For example, when a client sends an argument to a server in order toreceive a service from the server, a predetermined class file tointerpret the argument is often necessary. In this case, the clientsends location data of the class file with the argument to the server.If the IP address of a computer operating the client program is changedin cooperation with the computer's moving, and if the class file existsin the same computer, the client program updates the location data ofthe class file, and sends the updated location data to the server again.

[0043] Furthermore, when the server sends a processing result for theargument to the client, a predetermined class file to interpret theprocessing result is often necessary. In this case, the server sendslocation data of the class file with the processing result to theclient. If the IP address of a computer operating the server program ischanged in cooperation with the computer's moving, and if the class fileexists in the same computer, the server program updates the locationdata of the class file, and sends the updated location data to theclient again.

[0044] As mentioned-above, in the present invention, in a networkconnecting a plurality of terminals each including an environmentexecuting a program described by object-oriented language, even if anetwork address of a particular terminal is suddenly changed, the changeof the network address is reflected to the environment, and anotherterminal can continually access the particular terminal through thenetwork.

[0045] A memory can be used to store instructions for performing theprocess described above. The process may be performed with the aid of ageneral purpose computer or microprocessor. Such a memory can thus be aCD-ROM, floppy disk, hard disk, magnetic tape, semiconductor memory, andso on.

[0046] Other embodiments of the invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with the true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. An information processing apparatus, comprising:a program processing unit configured to execute a program described asan object-oriented language executed by a platform-independent machinelanguage; a monitor unit configured to monitor a change of a networkaddress of the information processing apparatus; and a referenceprovision unit configured to provide a new network address of theinformation processing apparatus for another information processingapparatus when said monitor unit detects the change of the networkaddress of the information processing apparatus.
 2. The informationprocessing apparatus according to claim 1, further comprising: a remotereference control unit configured to create a remote referencerepresenting a location address of a server object when the serverobject is generated in the information processing apparatus, the remotereference including a network address and a port number of theinformation processing apparatus.
 3. The information processingapparatus according to claim 2, wherein said provision unit registersthe remote reference in a directory service program in the otherinformation processing apparatus connected to a network, anotherinformation processing apparatus referring to the remote referencethrough the network to access the server object.
 4. The informationprocessing apparatus according to claim 3, when said monitor unitdetects the change of the network address of the information processingapparatus, wherein said remote reference control unit updates the remotereference by using the new network address, and wherein said provisionunit newly registers the updated remote reference in the dictionaryservice program.
 5. The information processing apparatus according toclaim 1, further comprising: a memory configured to store a class filedescribing a procedure necessary for another information processingapparatus to process a received object from the information processingapparatus.
 6. The information processing apparatus according to claim 5,wherein said remote reference control unit includes a management unitconfigured to manage a location address of the class file.
 7. Theinformation processing apparatus according to claim 6, when said monitorunit detects the change of the network address of the informationprocessing apparatus, wherein said remote reference control unit updatesthe codebase by using the new network address.
 8. The informationprocessing apparatus according to claim 7, wherein said memory stores aplurality of classes including the class file, and further comprising: aclass loader configured to store a location address of each of theplurality of classes, when said monitor unit detects the change of thenetwork address of the information processing apparatus, wherein saidclass loader updates the location address in the local codebase by usingthe new network address.
 9. The information processing apparatusaccording to claim 1, wherein the information processing apparatus is aservice terminal executing a server program to provide the service inresponse to a request from another information processing apparatus as aclient's terminal.
 10. A method in an information processing apparatus,comprising: executing a program described as an object oriented languageexecuted by a platform-independent machine language; monitoring a changeof a network address of the information processing apparatus; andproviding a new network address of the information processing apparatusfor another information processing apparatus when the change of thenetwork address of the information processing apparatus is detected. 11.The information processing method according to claim 10, furthercomprising: creating a remote reference representing a location addressof a server object when the server object is generated in theinformation processing apparatus, the remote reference including anetwork address and a port number of the information processingapparatus.
 12. The information processing method according to claim 11,further comprising: registering the remote reference in a dictionaryservice program in the other information processing apparatus connectedto a network, another information processing apparatus referring to theremote reference through the network to access the server object. 13.The information processing method according to claim 12, furthercomprising: when the change of the network address of the informationprocessing apparatus is detected, updating the remote reference by usingthe new network address, and registering the updated remote reference inthe dictionary service program.
 14. The information processing methodaccording to claim 10, further comprising: storing a class filedescribing a procedure necessary for another information processingapparatus to process a received object from the information processingapparatus.
 15. The information processing method according to claim 14,further comprising: managing a location address of the class file. 16.The information processing method according to claim 15, furthercomprising: when the change of the network address of the informationprocessing apparatus is detected, updating the codebase by using the newnetwork address.
 17. The information processing method according toclaim 16, further comprising: storing a plurality of classes includingthe class file, storing a location address of each of the plurality ofclasses, and when the change of the network address of the informationprocessing apparatus is detected, updating the location address in thelocal codebase by using the new network address.
 18. The informationprocessing method according to claim 10, wherein the informationprocessing apparatus is a service terminal executing a server program toprovide the service in response to a request from another informationprocessing apparatus as a client's terminal.
 19. A computer programproduct, comprising: a computer readable program code embodied in saidproduct for causing an information processing apparatus, said computerreadable program code having: a first program code to execute a programdescribed as an object-oriented language executed by aplatform-independent machine language; a second program code to monitora change of a network address of the information processing apparatus;and a third program code to provide a new network address of theinformation processing apparatus for another information processingapparatus when the change of the network address of the informationprocessing apparatus is detected.